Scientists at the University of California, San Francisco have identified a gene that plays a significant role in causing deafness. The implications of this discovery could profoundly impact future treatments for hearing loss.
Dylan Chan, MD, PhD at the University of California, San Francisco stated, "Millions of American adults lose their hearing due to noise exposure or aging each year, but it’s been a mystery what was going wrong." He further added, "We now have solid evidence that TMTC4 is a human deafness gene and that the unfolded protein response (UPR) is a genuine target for preventing deafness."
The research on deafness led by the team from the University of California, San Francisco and recently published in the Journal of Clinical Investigation Insight revealed that a specific mutation in the TMTC4 gene triggers UPR which results in hair cells' death in the inner ear. This study and previous ones imply that UPR could be responsible for certain types of hearing loss. According to a news release from Advanced Audiology & Hearing Care, this suggests that drugs like ISRIB that block UPR’s destructive effects could potentially prevent hearing loss.
Elliott Sherr, MD, PhD and Dylan Chan were co-senior authors of this groundbreaking paper. They studied mice exhibiting symptoms of age-related hearing loss. Sherr explained: "We expected mice with TMTC4 mutations to have severe brain defects early on... yet to our surprise, they seemed normal at first. But as those animals grew... they had gone deaf after they had matured." Sherr and Chan discovered that mutations in the TMTC4 gene resulted in excess calcium in the inner ear's hair cells leading to their death and disrupted UPR function - an effect similar to loud noises' impact.
This study's findings offer hope for innovative treatment methods for deafness. If UPR issues are indeed leading causes of hair cell damage, blocking UPR could prove to be a viable treatment option. Researchers are hopeful that individuals who need to take medications causing hearing loss or those exposed to loud noises regularly could potentially benefit from a UPR blocking drug and preserve their hearing. Diseases like Alzheimer’s or Lou Gehrig’s, which involve damaged nerve cells, might also see improvement with such a drug. Chan stated: "If there’s any way that we can get in the way of the hair cells dying, that’s how we’re going to be able to prevent hearing loss," according to a news release from Advanced Audiology & Hearing Care.
